Protein-resin bonded sheet abrasive



.il This invention relates y*tofabrasive products c1aifms4`- All 'parts and rcentages are by weight o; and methods of manufacturing the same; and unlessotherwise indicated. *y more particularly "it relates to adhesiveV coatedV Example 1 .manica Apr.zz,1947 'y y 2,419,194l

2,419,194 P no'rEIN-mzsm BoNDED siEE'r ABBASIVE t Allen C. "Barwell, `Kennett Square, rPa.;l assignor to Hercules Powder Company, I Wilmington,l

Del., a corporation of Delaware No Drawing; Application october 14'; 1944, Serial No.558.725 'j nomma V(cisl- 301) cellulosic sheet materials'such as, for example, e ysandpaper and emery cloth. r -5 One hundred parts of a mixture of 50 parts It has beencommon practice in-sandpaperand Aof y a pine'wood resin having a meltingrpolnt of emery cloth manufacture to usefordinary animal 114 C. (Hercules drop method). an acid numglue as the adhesive for securing abrasive grains ber of 90, and a gasoline insolubility of 85%, and to' thek surface oi'a material Vsnichjas'- paper vor 50 Darts ora pine woodreSin having a melting cloth.. yOne diihculty with previous sheet abrasive ,lo point of 86.7 C. (Hercules drop method); an acid Y products was that after being used 'for a short @number of 119, and a gasoline insolubility of time they tended to zum up.L This gumming is 64% was heated to its melting pointi To the caused by the inability of the glue coating to hold resin mixture. fat a temperature Just above its the abrasive grains vintact under conditionsv of melting point. was "added a solution of 9 parts oi' 1 use, Previousglue-coatedfpapers and cloths also 15 concentrated ammonium hydroxide (28% NH3) suilered from lack of water resistance, since the fin 10 partsof water, thus producing what was y glues which were'used were either water-'soluble essentially an ammonium Soap OIheI'ESn miX- or' water-dispersible. A further Ydii=i a.di'na,ntagel ture. In a Separate Vessel, 5`parts of acid casein found in the use ofv glueecoated papers `or cloths was wetted with 5 parts lof water and dissolved ,was *their poor Vaging; qualities. krrlheflattex-is 20 by adding'one part ofconcentrated ammonium generally attributed '-to a .breakdown of the glue hydroxidef The casein solution was addedto the binder itself as a consequence or bacterial action-.1 ammonium soap of. the resin mixture with thor- Now, in accordance' with this invention, it has ough mixing.: and theresulting' composition then* been iound'that'imp'roved abrasive products may4 was diluted bythe slow addition 01120 parts of bepre'pared fromfcellulosicgsheet materials fsuch'f25 water Aigof'iorman emulsion voff40%so1ids." To 3 as 'cloth or paper by coating thelatter with a l Darts of this emulsion wasslowly added with con`fy composition comprising a proteinaceousadhesivev stent stirring parts of an 'aqueous 50% hide glue,y i solution'havinga density of 30` Twadde11. Durfrom'about 30% to" about 95% petroleum Vhydxo- `ing the addition of the glue tothe emulsionaf carbon-insoluble material or' a Vpolyhy'dri'e alec: ,3 temperature of 55 C. was maintained. VThere;4

sulting adhesive composition was then applied by In the preparation of these new and improved means of a roller coating mechanism to cloth. sheet abrasive products, the pine woodresin 'or' l The` cloth was that ordinarily'used Vini-he manthe polyhydric alcohol ester thereof may beemul ui'acture ,of -ernery cloth, being 28 inches Vwi'de sifled in water using, forexample, casein and 35 ar 1d previously'sizedvwith va. 10% 'aqueous saluammonia as th'e emulsii'ying agents;V To the tion of hide glueg Abrasive particles consisting emulsions sol prepared, anu aqueous solution of'a ofaluminum oxide o1'Y 80-100 mesh size were approtelnaceous adhesive may then be slowly addpliedto 'the coated c1otli and the Vemery vcloth l ed and the resulting composition applied either allofwedto dry.' 'lhereafter, a dilute solution'l to paper or to cloth by any desirable means, 40,;(25%`solids)"f the I.cameladhesive was applied f suchj as by rollercoating.' vrI'liereai'ter,'abrasive las atopcoatand'the cloth again allowed to grains auch as garnet cremery are applied and The emery cloth was te'sted'on a cold-rolled steel Athe coating ilnally dried. Usually. top` coating bar having a diameter of!k three inches and turnof the adhesive "composition will be app1iedto ing in a lathe. The;adhesiveheld the kabrasive thedried'abrasive article and Ithe drying=proc- 45 particles satisfactorily, andthe remery, Vcloth ess repeated; Inv some'caseg it may .be'desirabley fr:proved .better than standard emery-cloths in reto'lnclude inf the adhesive 'composition ay smallf; Vspeci: to waterresistance. v Concerning the lat- Yamount ofa plastcizing agent.v` 5 if, .1.; ter, theemery clcithrof'tllisl invention-Stood up. Asfiliustrative ofthefvarious contemplated ad# 50% -better than standard emery cloth, which hesive compositions and abrasive productsde-l 50 used straightglue vas theadhesive, when both rivedV through use oi" said 'compositions severalV were used under identical moist conditions. 1

"Ec'amp le 2f z i be considered asv limiting the invention but areA AOne Vand three-'quarters parts of ,an aqueousf merely.. illustratingfthe inventivey concept whichz 50 %zf-hideA glue solution was slowly addedat a' is broadly setV `forth in thel kspecification and Y teniperatinfe of 552C. andv with constant ystirring drocarbons.

.to 1.75 parts of the resin emulsion described in Example 1, and to the resulting adhesive composition was added 0.19 part of a '15% solution of the monoethylene glycol ester of wood rosin aluminum oxide added. After drying, a dilute .v

solution of the adhesive coat and the cloth again dried. was tested as in Example 1, and it was found that under both dry and moist conditions this cloth held the abrasive particles more ilrmly than the straight glue adhesive used in ordinary emery cloths. The cloth proved to be 30% better under dry conditions and 60% better under moist conditions than standard emery cloths.

Example 3 One hundred parts of a pine wood resin having a melting point of 114 C. (Hercules drop method), an acid number of 98, and a gasoline insolubility of 80% was powdered so as to pass through a 1D0-mesh screen. 'I o the resin was added a casein solution made from parts of acid casein, Gyparts. of water, and parts of concentrated ammonium hydroxide (28% NH3). After mixing thoroughly the mixture was gently heated and 130 parts of water very slowly added with constant stirring to form an emulsion. The resulting emulsion had a solids content of 40%. To 3 parts of this emulsion was added at 55 C.,

slowly and'with constant stirring.. 3 parts of an was applied to cloth the coated cloth being allowed to dry. after, a top coat of thesame adhesive diluted to 22% solids was applied and the final product allowed 'to dry. The' emery cloth.`was tested desirable properties vof good adhesionL of thev abrasive particles, increased resistance Vto Iwear, and increased resistance to moisture. Furthermore,.the emery cloth proved better than stands in resistance to oils, greasesand petroleum hy- Y Example 4 The resin emulsion was heated to 55v C. and applied 'to cloth. Aluminum oxide (80-100 mesh) was spread on the coated cloth and the entire mass allowed to product allowed to dry. '.'This emery ample 3, but was somewhat less fiexible;

. Example-5 v Following' the procedure used in Example 3,

' an'e'mulsion was prepared from-36.4 parts of a pine wood resin having a melting pointiof 114 C."

ammonium hydroxide (28% NH3), 1.82 parts ofv wood rosin, and 54.50 parts of water. emulsion, warmed to 55 C., was slowly added an equal volume of an'aqueous 50% hide glue solution. The `adhesive composition so prepared was applied to paper by means of arollerv coat# ing mechanism and abrasive particles consisting described in Example 3 dry. A top `coat of the same emulsion dilutedr to solids was then applied and`r the nal casein, 3.64 parts of the ethylene glycol ester of To theaqueous 50% solution of hide glue. The adhesive 80-100 mesh aluminum oxide spread thereon,

as in Example 1 and foundY to have the same ard emery cloths utilizing glue as theadhesiv'e,

being tested was found t` have essentially the'` f same desirable qualities of that shown in lEx-A o Example 6 Following the procedure and proportions used in Example 1 a resin emulsion was prepared using a pine 'wood resin having a melting point of 86.7 C. (Hercules drop method), an-a'cid num-- ber of 119, and a gasoline insolubility of 64%. To the emulsionsoprepared was vadded atatemperature of C. an equal volumeof aqueous 50% animal glue. The resulting adhesive was applied to cloth, 80-100 mesh aluminum oxide spread on the coated cloth. and the entire mass allowed yA top coat ofthe same adhesive diluted to 22/ product allowed tordry. tested as in ,Example 1- and was found tobe cording to Example 1. ,n 1

'Y Example 7 One hundred parts of the glyceryl ester of a pine wood resin, the -resinhaving a melting Ypoint of 115 C. (Hercules drop method), number of v93, anda gasoline insolubility of 88%, was powdered so as to pass through a 1D0-mesh screen. Following the procedure of Example 3 anemulsion ofthe ester was l prepared. To this emulsion; heated to 55 C., was slowly added with constant stirring (55,9 C.) aqueous 50% solution of hide glue. The resulting adhesivecomposition was spread on a piece of cloth Aby meansof a roller,l coating mechanism and 80-100 mesh aluminum oxide particles composed off added. Afterrlrying,y a ltopfioat the same adhesive ,diluted with an equal volume of. water was applied to the cloth and the 'unal Iproductallowed to dry. When the emery cloth was tested on a cold-rolled steel bar l'urning in a lathe-it was found to ybe superior to emery cloths prepared using astraight glue'coating. The Iabrasive*particles were more firmly held, the tendency to Afgum up" was less, andthe cloth was more` resistant to the action of water, oils, greases, petroleumr hydrocarbons,l and alkalies. l y

` ,l )Eaafitple'fl Y Y Following the prpedure gf Exsuipm alla 40% solidsvemulsionl was preparedfrom .100 parts ofy the ethylene glycol ,estervof a pine-woodY resin, i

the resin having 'a meltingpoint of V114 C. (Hercules drop method) an acid number of 100and a (Hercules drop method), an acid number of 100, and a gasoline insolubility of V82%, 3.64 parts of` equal volume of warm (55 gasoline insolubility. of 82%. To vthis emulsion at 55,j C. was added slowly ,and with stirring an C.) aqueous v50%l solution of hide glue. f' :The resultingadhesivewas spread on a. piece of .paper and -100 mesh aluminum oxide applied as'theabrasive.l After drying, a top coat consisting of a.A 22% ysolids solution of the above yadhesive was lapplied,v and the final product allowed Ato dry. The sandpaper was tested inregard to resistance toiwear,A and resistance'to'water, alkalies, oils, vgreases, and petroan acid y an equalwolume of warm j Example 9 Following the method shown in Example 1 a 40% solids emulsion was prepared from the glyceryl ester of a pine wood resin, the resin having a melting point of 89 C. (Hercules drop meth- 0d), an acid number of 124, and a gasoline insolubility of 57%. This emulsion was applied at 55 C. to a. piece of cloth and 80-100 mesh aluminum oxide spread thereon as the abrasive. Afterfdrying, a top coat consisting of the above emulsion diluted with an equal volume of water to produce an adhesive of 20% solids was applied and the final product allowed to dry. On testing the emery cloth it exhibited the desirable properties found in connection with the emery cloth of Example'?. l The pine wood resin which is useful in the rosin in the wood or by a process which involves separation of the rosin, may be used. AThe resin l material preferably contains at least about 30% rosin, which is ruby red in color and is derived compositions of this invention may be any portion or substantially all of thatdark-colored fraction of pine wood resin which can be extracted from the wood with aromatic hydrocarbons and which is characterized by a petroleum hydrocarbon insolubility of from about 30% to about 95%.

'I'he wood resin extract of pine wood such as.

is obtained by extracting pine wood with benzene consists of pale rosin, gasoline-insoluble resinous material and color bodies. Frequently such extract contains 15% or more of gasoline-insoluble resinous material. Upon the treatment of such resinous extract to separate therefrom a fraction l of pale rosin there is formed one or more fractions containing the balance of the resinous materlal derived from the pine wood. One or more of such remaining fractions may be used as the resin material in this invention. The nonrosin portion of the pine Wood extract may be separated by appropriate processes into a fraction of substantially gasoline-insoluble resinous material and a dark-colored intermediate fraction lying between the substantially gasoline-insoluble fraction and rosin.- It is impossible to effect an absolutely clean separation between the gasolineinsoluble resinous material and the rosin. By the preparation of adark-c'olored intermediate fraction containing some gasoline-insoluble resinous material and the color bodies, a very good separation of the pine wood extract into rosin, gasoline-insoluble resinous material, and into this intermediate fraction is eiiected.

As one of the pine Wood resins of this invention, it is preferable to use the dark-colored intermediate fraction largely insoluble in petroleum hydrocarbons and obtained by the refining of impure wood rosin to pale grades by means of a selective solvent for color bodies such as furfural, or a selective adsorbent such as fullers earth. Such an intermediate fraction contains at least '30% and up to about 80% by weight of a gasolineeither by a process which involves leaving the of gasoline-insoluble resinous material, varying therefrom up to about The dark-colored fraction referred to above is a product resulting from the process used in decolorizing rosin. For example, so-called FF from pine wood by extraction with benzene followed by evaporation of the benzene and extraction of the resinous residue with a petroleum hydrocarbon'such as hot petroleum ether or hot gasoline, is decolorized by adding furfural to the hot solution, agitating the mixture, and then allowing the mixture to form a liquid layer system in which Ithe furfural layer contains the unsaponiflables and coloring bodies in the original FF rosin and the gasoline layer contains the pale rosin. The furfural layer is separated from the gasoline layer and distilled to recover the furfural, the-residue remaining being the dark-colored intermediate fraction referred to. This fraction contains most of the coloring bodies and a larger proportion o1' the unsaponiiiables from the original FF rosin as well as a good proportion of the rosin acids. It contains a large proportion of oxidized rosin acids and, therefore, is only partially soluble in petroleum hydrocarbon solvents at room temperature. The percentage of gasoline-insolubles varies from about 30% to about 80% by weight. It has a higher flow point, a much higher viscosity, lower acid number and a higher unsaponifia'ble content than FF wood rosin. However, the saponiilcation number is not correspondingly lower, indicating, thereby, a higher ester content. In addition it is noncrystallizing. Such a fraction is characterized by the following approximate analysis:

Petroleum ether insoluble f 30-80% A typical example of such a fraction had the following analysis: acid number, 124; saponiflcation number, melting point (drop), 89 C.; gasoline-insoluble, 57%; unsaponifiable matter, 12%; Lovibond color, dark; ash content,'0.03%. The substantially gasoline-insoluble fraction referred to above may be prepared from pine wood by the processes set forth in U. S. patents to Hall, Nos. 2,193,026 and 2,221,540. This fraction is characterized by being substantially completely insoluble in petroleum hydrocarbons such as gasoline. The gasoline-soluble portion of this fraction rarely exceeds 20% by Weight. This fraction may be said to be the gasoline-insoluble resin contained in pine wood. For example, the extraction of pine wood with benzene yields a mixture of this fraction and FF rosin. Upon treatment of the resinous mixture with a mixture of gasoline and a relatively small volume of furfural the substantially gasoline-insoluble fraction goes into solution in the. furfural while the FF rosin goes into solution in the gasoline. The two layers are allowed to separate and the resinous materials then may be recovered from the separated layers in any suitable manner.

The substantially r:ompletely gasoline-insoluble fraction is, in general.' defined by the following characteristics: Substantial insolubility in petroleum hydrocarbons, the insolubility being of the order of at least 80%, substantially complete solubility in alcohol, a methoiw content of from about 3% to about 7%, an acid number of from about 80 to about 110, a melting point by the Hercules drop method of from about 95 C. to about 125 C., a saponiflcation number of from about 135 to about 145, and a noncarboxylic hydroxyl content of from about 5% to about 9%. A typical specimen had the following characteristics: Drop melting point, 115 C.; acid number, 93; gasoline-insoluble matter, 88%; toluene-insoluble matter, 80%; saponiflcation number, 140; ash content. 0.02%.

In general the pine wood resins employed in carrying out the present invention and which are typified by the dark-colored intermediate fraction of color bodies referred to at length above and the substantially completely gasoline-insoluble fraction and blends thereof may be defined as the resins naturally occurring in pine wood and characterized by a gasoline-insolubility of about 30% to about 95%, an unsaponifiable content of from about 5% to about 20%, a melting point above 85 C. and preferably about 90 C., and an acid number of not over about 140.

The examples have described the use of the glyceryl and ethylene glycol esters of the pine wood resins contemplated by this invention, but other polyhydric alcohol esters of the aforemenfrom about 9% to about 32% on abrasive particles, and drying. The emulsion,

of the adhesive composition used as a top coat will generally be more dilute than the emulsion used in applying the main coating. The latter emulsion preferably has a totaly solids content of about 40%, -but the top coat emulsion may range total solids, and

l from about to about 25% total solids will be tioned resins, such as those lderived from diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, tetr'amethylene glycol, erythritol, pentaerythritol, mannitol, and the like, may be employed.

The pine wood resins and esters thereof contemplated by this invention may be 'present in the final adhesive composition in amounts ranging from about 20% to about 100% based on the total solids. It is preferable; however, that from about 40% to about 50% of the total solids be the resin or esters thereof.

Although the examples have shown only the use of hide glue, other animal proteinaceous materials, such as blood, albumen glue, casein glue,l fish glue, isinglass, bone glue, cartilage glue, skin glue, and the like, may be utilized. Furthermore, vegetable proteinaceous adhesives, such as those prepared from zein, soya, bean protein, etc., may be used. 'It should be realized that in the use of the aforementioned glues and adhesives, compositions generally recognized in the art are contemplated.

The proteinaceous adhesives utilized in this invention may be present in amounts up to about 80% hesive composition. It is preferable, however, that the proteinaceous adhesive consists of from about 50% to about 60% of the total solids, and a particularly advantageous amount is about In some of the examples which set forth the use of the fraction of pine wood resin contemplated by this invention the ethylene glycol ester of wood rosin has been shown as an ingredient of the adhesive composition, functioning as a plasticizer. Other materials, however, may be used in like capacity. For example, the diethylene glycol ester of rosin, the monoand diethylene glycol esters of hydrogenrated rosin, the monoand diethylene glycol esters of disproportionated rosin, the monoand diethylene glycol esters of the adduct of maleic anhydride and the methyl ester of rosin, the mono, diand triethylene glycol esters of based on the total solids of thefinal ad'- over the prior art products.

particularly advantageous.

The operable temperature for the application of the adhesive emulsions of this invention will be in the range of from about 50 C. to about C., although the preferred temperature will be about 55 C. While the top coat adhesive will preferably be applied at about 55 C., it may be applied, because of its dilute nature, at temperatures ranging from about 20 C. to about 70 C.

In the preparation of emery cloth Example l has described the cloth base as being twentyeight inches wide and previously sized with a 10% aquefius solution of hide glue. The purpose of the gluie sizing is to prevent penetration of the principal adhesive below the surface of the cloth. Inplace of the 10% hide glue solution ordinariiyiemployed in sizing cloth to be utilized in emery jcloth manufacture the adhesive compositions bf this invention may be used. By so doing a v ry satisfactory emery cloth base may be prepa ed which does not permit penetration of the m in adhesive coating, and which is more advantal eous than ordinary glue size in that the sized e ery cloth base is less sticky in warm or humid eather. For sizing purposes the adhesive co positions of this invention may be applied as em sions having from about 5% to about 20% total d lids, and a value of about 10% total solids will be particularly advantageous. Depending upon/ the viscosity of the adhesive emulsion, the latter may be applied at a, temperature of about 20/C. to about 55 C., using sizing procedures well known in the art, and the product dried at aftemperature of about 100 C. to about 120 C. The sheet abrasive products prepared in accordance with this invention present advantages Sandpaper or emery cloth prepared in accordance with the present processes have been shown to exhibit a definite improvement in the tendency to gum up" under conditions of actual use, consequently, they may be used longer than the prior art products. These novel sheet abrasive products are also interesting inasmuch as they provide superior water and oil resistance as compared with prior art products and have excellent resistance to decomposition with age. Furthermore, since the cost per pound of the resin emulsions described herein is cor.- siderably less than tlrat of aqueous 50% glue solutions per pound, the cost of the improved adhesive compositions of this invention is a great deal lower than when glue alone is used.

What I claim and desire to protect by Letters Patent ist l. An abrasive product comprising a backing of a cellulosic sheet material, a coating thereon the adduct of maleic comprising a proteinaceous adhesive and a ma- .comprising a paper backing,

teria] selected from the group consisting o1' a pine wood resin having a petroleum hydrocarbon insolubility of from about 30% to about 95% and a polyhydric alcohol ester of said resin, and abrasive grains embedded in said coating.

2. An abrasive product comprising a backing of a cellulosic sheet material, a coating thereon comprising a proteinaceous adhesive and from about to about 50% by weight based on the total solids present in the coating of a material `10 selected from the group consisting of a pine Wood resin having a petroleum hydrocarbon insolubility of from about to about 95% and a polyhydric alcohol ester of said resin, and abrasive grains embedded in said coating.

l 3. An abrasive product comprising a backing of a cellulosic sheet material, a coating thereon comprising a proteinaceous adhesive and from about to about 50% by weight based on the .total solids present in the coating of a material 20 ,'hydric alcohol ester of a pine wood resin having 35 '9. petroleum hydrocarbon insolubility of from about 30% to about 95%, embedded in said coating.v

6. An abrasive product comprising a backing and abrasive grains of a cellulosic sheet material, a coating thereon 40 comprising an animal proteinaceous adhesive and a pine wood resin having a petroleum hydrocarbon insolubility of from about 30% to about 95%, and abrasive grains embedded in said coating.

7. An abrasive product comprising a backing of a cellulosic sheet material, a coating thereon comprising animal glue anda pine wood resin having a petroleum hydrocarbon insolubility of from about 30% to about 95 and abrasive grains embedded in said coating.

8. As a new article of manufacture, sandpaper a coating thereon comprising animal glue and a pine wood resin to about 95%, and 30 having a petroleum hydrocarbon insolubility of from about 30% to about 95%, and abrasive grains embedded in said coating.

9. An abrasive product comprising a backing 5 of a cellulosic sheet material, a coating thereon comprising a proteinaceous adhesive and a, pine wood resin having a petroleum hydrocarbon insolubility of from about to about 95%, and abrasive grainsiembedded in said coating.

l0. An'abrasive product comprising a backing of a, cellulosic 'sheet material, a coating thereon` comprising an animal proteinaoeous adhesive and a pine wood resin having a petroleum hydrocarbon insolubility of from about 80% to about 95%,

5 and abrasive grains embedded in said coating. y

11. An abrasive product comprisingY a backing of a cellulosic sheet material, a coating thereon comprising animal glue and a pine wood resin having a petroleum hydrocarbon insolubility of from about 80% to about 95%, and abrasive grains embedded in said coating.

12. As a new article of manufacture, emery cloth comprising a cloth backing, a coating thereon comprising animal glue and a pine wood 5 resin having a petroleum hydrocarbon insolubility of from about 80% to about 95%, and abrasive grains embedded in said coating.

13. An abrasive product comprising a backing of a cellulosic sheet material, a coating thereon comprising a proteinaceous adhesive and the glyceryl ester of a pine Wood resin having a petroleum hydrocarbon insolubility of from about 30% to about and abrasive grains embedded in said coating.

14. An abrasive product comprising a backing of a cellulosic sheet material, a coating thereon comprisingv a proteinaceous adhesive and the ethylene glycol ester of a pine wood resin having a petroleum hydrocarbon insolubility of from about 30% to about 95%, embedded in said coating.

ALLEN C. BARWELL.

REFERENCES CITED 'The following references are oi. record in the and abrasive grains le of this patent:

UNITED STATES PATENTS Number Name Date 172,162 Peabody Jan. 11, 1876 1,468,960 Crupi Sept, 25, 1923 2,127,298 Isaacs Aug. 18, 1938 2,325,172

Borglin July 27, 1943 

